1. Field of the Invention
The present invention relates to tank trucks, and more particularly, to means for resiliently supporting the tank on the truck frame.
2. Prior Art
There are a variety of tank trucks in commercial operation today most of which employ a substantially cylindrical tank which is secured in a variety of ways to a truck frame which in turn is supported by a suspension system on the axles of the truck, along with the cab. Many of these tank trucks have the tanks rigidly secured to the truck frame so that the only suspension or "give" during normal operation of the truck is provided by the suspension system of the truck.
During normal operation of such tank trucks the connections between the tank and the frame are subject to a variety of stress conditions due to turning, stopping, accelerating, etc. These loads cause cyclical stresses in the connections between the tank and the frame which eventually can result in fatigue failure if the support mountings are not designed to be adequately strong. As a result, the connections between the tank and the truck frame are usually overly massive in order to provide adequate safety margin to prevent such possible failures. Since the connection between the tank and the frame is generally a rigid connection the stresses produced in the mounting brackets are more severe than they would be if a more resilient mounting connection was provided and thus the mounting brackets must be additionally "beefed up" because of these higher stresses.
In addition to these deficiencies in such prior art tank trucks, additional stresses are produced due to the fact that the tank truck is mounted somewhere above the main frame of the truck and suspended on support legs which are rigidly secured to both the tank and the frame. This provides an increased moment about the connection points which further increases stresses under normal operation of the truck. This in turn, therefore, requires additional increasing of the massiveness of the support between the tank and the truck in order to provide adequate safety margins for the level of stresses involve.